Hi. Thank you for your reply.
But that post instructs us to remove old objects laid about by older versions of PSC, and I don't have that problem. In fact, I'm almost sure the problem is related to changing the time frame. If you would be so kind to watch this video, you shall see it happen:
https://gofile.io/d/e1rXki
Note that you can download the video file or stream it right from the page.
Also note that I have changed the font and color of the lines and labels, but I didn't change anything else and the problem was already there before I changed anything.